title: Diversity-oriented general protocol for the synthesis of privileged oxygen scaffolds: pyrones, coumarins, benzocoumarins and naphthocoumarins.
abstract: A new general methodology for the synthesis of various functionalized privileged oxygen heterocyclic scaffolds, viz. pyrones, coumarins, and benzannulated coumarins, is developed. The synthesis proceeds through carbanion-induced ring transformation of lactones with various methylene carbonyl compounds followed by DDQ-mediated unprecedented oxidative cleavage of oxaylidenes intermediates. Studies of the mechanism of the conversions of oxaylidene intermediates into corresponding carbonyl compounds in the presence of DDQ revealed that the reactions took place via the formation of a Michael adduct instead of an intermolecular charge transfer complex. The methodology offers the fabrication of diverse privileged scaffolds with tolerance for many functional groups onto the oxygen heterocyclic molecular framework.
authors.affiliation: Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow, India. atul_goel@cdri.res.in
authors.forename: Atul
authors.initials: A
authors.lastname: Goel
authors.forename: Gaurav
authors.initials: G
authors.lastname: Taneja
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Raghuvanshi
authors.forename: Ruchir
authors.initials: R
authors.lastname: Kant
authors.forename: Prakas R
authors.initials: PR
authors.lastname: Maulik
mesh_terms: D001555:Benzene Derivatives / Q000138:chemical synthesis; D003374:Coumarins / Q000138:chemical synthesis*; D003500:Cyclization; D007783:Lactones / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*; D011753:Pyrones / Q000138:chemical synthesis*
chemical_list: D001555:Benzene Derivatives; D003374:Coumarins; D007783:Lactones; D011753:Pyrones; D010100:Oxygen